This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This is an NIH-sponsored multi-center phase 1-2 trial comparing the safety and immune responses of a clade 2 avian influenza vaccine in prior recipients of a clade 1 vaccine versus placebo. Subject are randomized to get either a low dose (15 [unreadable]g) or a high dose (90 [unreadable]g) of the vaccine.